Telecommunication regulations encourage that multi-line telephone systems (MLTS) report the exact location of a caller requesting emergency services to the public safety answering point (PSAP). Unlike traditional private branch exchange (PBX) solutions, multi-line telephone systems that make use of voice over Internet protocol (VoIP) solutions are unable to report the exact location of a caller.
In order to provide location information in connection with VoIP telephone systems, a number of approaches have been suggested. For example, static records may be maintained regarding the location of each communication station. In order to provide automated retrieval of such information, it may be stored as a database record associated with the extension. However, static databases are not practical to maintain in connection with VoIP systems, because of the mobile nature of VoIP.
Another solution involves the use of simple network management protocol (SNMP) to query a phone to determine the subnet that the phone or communication device is connected to. However, such systems are incapable of providing accurate location information regarding particular devices. Furthermore, depending on the network architecture, the subnetwork information may have little relation to the physical location of a communication device.
Other systems for determining the location of a communication device make use of the global positioning system (GPS). GPS is capable of providing accurate location information regarding a device. However, GPS based systems are expensive, and do not work well inside buildings and concrete structures.
Still other systems have proposed the use of radio frequency transponders that are programmed to deliver significant information related to a call when a call is made. However, the use of such a transponder requires programming of the device at the time of the emergency. In addition, in such arrangements, the transponder presents a single point of failure.